The early extracellular binding of SP82G DNA in transfection and marker rescue in Bacillus subtilis is being studied. The aim is to identify the cellular components involved in the initial binding events. Control experiments involving the normal phage infection process reveal that an early event is the binding of infecting DNA to cell membrane. A specific region of the SP82G molecule is initially involved in this step. The binding proces requires RNS synthesis but not protein synthesis. Experiments are proposed to determine whether the transfection process involves a similar binding to the same membrane component. In addition to this approach, a number of Bacillus subtilis mutants defective in competence have been isolated and introduced into an isogenic background. Of 93 mutants examined, 47 behave as single genes in transformation assays. The isogenic single gene mutants are in the process of being examined for phenotype. They fall into a wide range of phenotypes; some which fail to bind DNA, others which bind DNA but do not transport it into the cell, still others which, although successful in the preceeding steps, do not integrate it into the genome. The relationship of the nature of the defects to the binding and entry events which are seen in wild-type cells is under investigation.